NAIROBI, Kenya (AP) — Four terror suspects charged with killing 76 people who watching the 2010 World Cup soccer final on TV in Uganda claimed they were physically abused during interrogations by FBI agents, an international rights organization reported Tuesday.

The suspects said men who identified themselves as FBI agents beat them up during questioning between 2010 and 2011 in the East African country, the Open Society Justice Initiative said in a report.At FBI headquarters in Washington, spokesman Paul Bresson said allegations that FBI employees mistreated or abused detainees were without merit.

"The FBI is responsible for investigating overseas terrorist attacks against U.S. persons or U.S. institutions. When investigating cases overseas, all FBI personnel operate within the guidelines established by the Attorney General as well as all other applicable laws, policies and regulations," Bresson said.

Selemi Hijar Nyamandondo, who is from Tanzania, alleged that an interrogator hit him in the eye, causing his glasses to break, his eye to bleed and making him collapse on the ground. Nyamandondo also said when he attempted to stand up, a Ugandan official in the room punched him in the chest, causing him to fall down.

Human rights groups say Kenya and Tanzania circumvented their extradition laws to illegally deport suspects to Uganda, where they could be interrogated at length by local and foreign agents without scrutiny.

Uganda has been criticized internationally for human rights abuses by its security forces.Omar Awadh Omar, who is Kenyan, said he was punched and slapped" by men who said they were FBI agents.

Omar, who is among six people blacklisted earlier this year by the Obama administration for providing support to an al-Qaida affiliated terror group, also provided the name of an alleged U.S. "security officer" who struck him in the knee with a hard object, the report said.

Another Kenyan suspect, Yahya Suleiman Mbuthia, alleged that during his first interrogation a blue-eyed man who identified himself as an FBI officer "cocked his gun as if he were going to shoot me, saying there was a bullet inside with my name on it." Mbuthia also alleged that an FBI officer hit him on the back of the head with his fist.

Hussein Hassan Agade, another Kenyan, gave the name of a man who he said introduced himself as an FBI official and kicked him in the abdomen, grabbed him hard by the neck, and threatened to send him to Guantanamo Bay, the report said.

The four men who claim they were abused are among 14 illegally transferred to Uganda without extradition proceedings in a practice known as rendition. Two of the suspects have since been released, according to the report.

The report said the U.S. Department of Justice confirmed that assistance in response to the bombings came not only from FBI agents, but also from New York Police Department or NYPD detectives attached to the New York Joint Terrorism Task Force (JTTF). The Department of Justice also reported that since August 2010, U.S. government attorneys and JTTF personnel "at the request of Ugandan law enforcement, travelled to Uganda and provided assistance to the Ugandan investigators and prosecutors."

The four suspects who claim to have been abused were arrested on different dates following the July 11, 2010, attack that killed 76 people as large crowds watched the World Cup final on TV in Uganda's capital city of Kampala. An American was among those killed.

Al-Shabab, a Somali group affiliated with al-Qaida, claimed responsibility for the attacks and said it targeted Uganda because Ugandan troops belonging to an African Union peacekeeping force in Somalia have killed Somali civilians.

The Open Society Justice Initiative asked that the U.S. government release information about its response to the allegations and urged that an investigation take place, if it hasn't already.Associated Press Writer Frederic J. Frommer contributed to this report from Washington DC.